This invention relates to an ultrasound diagnostic apparatus and an ultrasound image display method. More specifically, this invention relates to an ultrasound diagnostic apparatus and an ultrasound image display method to display the puncture guide line so as to be superimposed on an ultrasound image.
In the medical field, an ultrasound diagnostic apparatus using an ultrasound image has been put into practical use. Generally, this kind of ultrasound diagnostic apparatus includes an ultrasound probe with an integrated transducer array and the apparatus body connected to the ultrasound probe, and generates an ultrasound image by transmitting an ultrasonic wave toward a subject from the ultrasound probe, receiving an ultrasonic echo from the subject using the ultrasound probe, and processing the reception signal electrically in the apparatus body.
In recent years, the ultrasound diagnostic apparatus is also used when inserting the puncture needle into the subject to sample specific body tissue and performing a biopsy or the like. In this ultrasound diagnostic apparatus, the puncture needle is moved to target body tissue while checking the movement of the puncture needle within the subject through an ultrasound image displayed on a monitor by transmitting an ultrasound beam toward the subject from the ultrasound probe and receiving an ultrasound beam reflected from the subject using the ultrasound probe. In addition, a puncture guide line for guiding the puncture needle from the surface of the subject to the target body tissue is displayed on the monitor so as to be superimposed on the ultrasound image, so that the arrival of the puncture needle at the target body tissue can be supported by the puncture guide line. However, since the puncture needle is embedded in the surrounding body tissue in the ultrasound image, it has been difficult to check the position clearly.
Therefore, as a technique for clearly displaying the position of the puncture needle in an ultrasound image, for example, as disclosed in JP 2007-195867 A, dividing an ultrasound image into a region including a puncture guide line and the other region and performing image processing, such as narrowing a dynamic range, on the region including the puncture guide line has been proposed. In the ultrasound diagnostic apparatus disclosed in JP 2007-195867 A, since the puncture needle is emphasized by performing image processing on the region including the puncture guide line in the ultrasound image, it is possible to make the position of the puncture needle clear.
In addition, since the puncture needle or the target body tissue overlaps the puncture guide line, there has been a problem in that it is difficult to check these positions in detail. Therefore, an ultrasound diagnostic apparatus has been developed that can check the positions of a puncture needle N and body tissue T in detail by freezing a real-time ultrasound image B, which is displayed on a monitor 21, first as shown in FIG. 8A and then not displaying a puncture guide line G, which is displayed so as to be superimposed on the ultrasound image, as shown in FIG. 8B.
However, at the time of returning from the freeze operation to the live operation to display the real-time ultrasound image B in order to continue the puncture, an operation to display the puncture guide line G should be performed again since the puncture guide line G is not displayed. Accordingly, it has been difficult to perform smooth switching from the freeze operation to the live operation to continue the puncture. For this reason, when the live operation and the freeze operation are switched many times while maintaining a puncture state, for example, when performing puncture by changing the angle of the puncture needle N little by little while performing switching between the freeze operation and the live operation, an operation to display the puncture guide line G should be performed at each time of returning to the live operation. This may disturb the puncture.